Android自定義實(shí)現(xiàn)六邊形按鈕繪制

public class PolygonSettingView extends View {    /**     * View默認(rèn)最小寬度     */    private static final int DEFAULT_MIN_WIDTH = 100;    /**     * 畫筆     */    private Paint mPaint;    /**     * 控件寬     */    private int mViewWidth;    /**     * 控件高     */    private int mViewHeight;
    /**     * 多邊形的邊數(shù)     */    private int mNum;    /**     * 最小的多邊形的半徑     */    private float mRadius;    /**     * 360度對(duì)應(yīng)的弧度（為什么2π就是360度？弧度的定義：弧長(zhǎng) / 半徑，一個(gè)圓的周長(zhǎng)是2πr，如果是一個(gè)360度的圓，它的弧長(zhǎng)就是2πr，如果這個(gè)圓的半徑r長(zhǎng)度為1，那么它的弧度就是，2πr / r = 2π）     */    private final double mPiDouble = 2 * Math.PI;    /**     * 多邊形中心角的角度（每個(gè)多邊形的內(nèi)角和為360度，一個(gè)多邊形2個(gè)相鄰角頂點(diǎn)和中心的連線所組成的角為中心角     * 中心角的角度都是一樣的，所以360度除以多邊形的邊數(shù)，就是一個(gè)中心角的角度），這里注意，因?yàn)楹罄m(xù)要用到Math類的三角函數(shù)     * Math類的sin和cos需要傳入的角度值是弧度制，所以這里的中心角的角度，也是弧度制的弧度     */    private float mCenterAngle;    /**     * 顏色     */    private int mColor;    /**     * 中心小圓的半徑     */    private float mSmallCircleRadius;    /**     * 線寬     */    private float mLineWidth;
    public PolygonSettingView(Context context) {        this(context, null);    }
    public PolygonSettingView(Context context, @Nullable AttributeSet attrs) {        this(context, attrs, 0);    }
    public PolygonSettingView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        init(context, attrs, defStyleAttr);    }
    private void init(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {        initAttr(context, attrs, defStyleAttr);        //取消硬件加速        setLayerType(LAYER_TYPE_SOFTWARE, null);        //畫筆        mPaint = new Paint();        mPaint.setAntiAlias(true);        mPaint.setStyle(Paint.Style.STROKE);        mPaint.setColor(mColor);        mPaint.setStrokeWidth(mLineWidth);    }
    private void initAttr(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {        //默認(rèn)邊數(shù)和最小邊數(shù)        int defaultNum = 6;        int minNum = 3;        int defaultColor = Color.argb(255, 0, 0, 0);        int defaultLineWidth = dip2px(context, 1.5f);        if (attrs != null) {            TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.PolygonSettingView, defStyleAttr, 0);            mColor = array.getColor(R.styleable.PolygonSettingView_psv_color, defaultColor);            int num = array.getInt(R.styleable.PolygonSettingView_psv_num, defaultNum);            mNum = num <= minNum ? minNum : num;            mLineWidth = array.getDimension(R.styleable.PolygonSettingView_psv_line_width, defaultLineWidth);            array.recycle();        } else {            mColor = defaultColor;            mNum = defaultNum;        }        //計(jì)算中心角弧度        mCenterAngle = (float) (mPiDouble / mNum);    }
    @Override    protected void onSizeChanged(int w, int h, int oldw, int oldh) {        super.onSizeChanged(w, h, oldw, oldh);        mViewWidth = w;        mViewHeight = h;        //計(jì)算最小的多邊形的半徑        mRadius = (Math.min(mViewWidth, mViewHeight) / 2f) * 0.95f;        //計(jì)算中心小圓的半徑        mSmallCircleRadius = (Math.min(mViewWidth, mViewHeight) / 2f) * 0.3f;    }
    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        //將畫布中心移動(dòng)到中心點(diǎn)        canvas.translate(mViewWidth / 2, mViewHeight / 2);        //畫小圓        drawSmallCircle(canvas);        //畫多邊形        drawPolygon(canvas);    }
    /**     * 畫小圓     */    private void drawSmallCircle(Canvas canvas) {        canvas.drawCircle(0, 0, mSmallCircleRadius, mPaint);    }
    /**     * 畫多邊形     */    private void drawPolygon(Canvas canvas) {        //多邊形邊角頂點(diǎn)的x坐標(biāo)        float pointX;        //多邊形邊角頂點(diǎn)的y坐標(biāo)        float pointY;        //總的圓的半徑，就是全部多邊形的半徑之和        Path path = new Path();        //畫前先重置路徑        path.reset();        for (int i = 1; i <= mNum; i++) {            //cos三角函數(shù)，中心角的鄰邊 / 斜邊，斜邊的值剛好就是半徑，cos值乘以斜邊，就能求出鄰邊，而這個(gè)鄰邊的長(zhǎng)度，就是點(diǎn)的x坐標(biāo)            pointX = (float) (Math.cos(i * mCenterAngle) * mRadius);            //sin三角函數(shù)，中心角的對(duì)邊 / 斜邊，斜邊的值剛好就是半徑，sin值乘以斜邊，就能求出對(duì)邊，而這個(gè)對(duì)邊的長(zhǎng)度，就是點(diǎn)的y坐標(biāo)            pointY = (float) (Math.sin(i * mCenterAngle) * mRadius);            //如果是一個(gè)點(diǎn)，則移動(dòng)到這個(gè)點(diǎn)，作為起點(diǎn)            if (i == 1) {                path.moveTo(pointX, pointY);            } else {                //其他的點(diǎn)，就可以連線了                path.lineTo(pointX, pointY);            }        }        path.close();        canvas.drawPath(path, mPaint);    }
    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        setMeasuredDimension(handleMeasure(widthMeasureSpec), handleMeasure(heightMeasureSpec));    }
    /**     * 處理MeasureSpec     */    private int handleMeasure(int measureSpec) {        int result = DEFAULT_MIN_WIDTH;        int specMode = MeasureSpec.getMode(measureSpec);        int specSize = MeasureSpec.getSize(measureSpec);        if (specMode == MeasureSpec.EXACTLY) {            result = specSize;        } else {            //處理wrap_content的情況            if (specMode == MeasureSpec.AT_MOST) {                result = Math.min(result, specSize);            }        }        return result;    }
    public static int dip2px(Context context, float dipValue) {        final float scale = context.getResources().getDisplayMetrics().density;        return (int) (dipValue * scale + 0.5f);    }}